Vibration welding apparatus and welding method

ABSTRACT

A vibration welding apparatus and a method for executing vibration welding of three or more work pieces made of a thermoplastic material to make them integral in a sandwich shape, comprises an upper tool means supporting a first work piece so as to apply a lateral motion to it by a vibration means, a lower tool means capable of supporting a plurality of second work pieces to be welded to at least both surfaces of the first work piece, and a means capable of actuating the lower tool means in such a manner as to move the second work pieces vertically by an elevating means so as to align with the first work piece, and move the second work pieces toward the first work piece laterally by a slide actuating means so as to bring them into contact with the first work piece.

INCORPORATED-BY-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No.11/440,066, filed May 25, 2006, now U.S. Pat. No. 7,637,300, the entirecontents of which is incorporated by reference.

TECHNICAL FIELD

The present invention relates to the field of vibration weldingtechnology based on frictional heating, a result of applying a relativevibration (motion) to a plurality of work pieces made of thermoplasticmaterial.

BACKGROUND ART

In the embodiment of the invention of Japanese Unexamined PatentPublication No. 9-85833 (Patent Document 1), there is disclosed atechnology for executing a vibration welding process by bringing twowork pieces made of a thermoplastic material into contact with eachother in a face to face manner.

In the embodiment of the invention of Japanese Unexamined PatentPublication No. 9-151723 (Patent Document 2), there is disclosed atechnology for executing vibration welding of two work pieces broughtinto contact with each other by a fixed side tool and a vibration sidetool.

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

It is impossible to weld three or more work pieces to each other in asandwich shape in a single weld, by the technologies disclosed in thedocuments 1 and 2 mentioned above.

The problem to be solved by the present invention exists as it is hardto develop a technology for integrally welding three or more work piecesin accordance with sequential working steps.

Further, the following problems typically occur while manufacturing thisconventional thermoplastic product.

For example, a center console box (a storage box) arranged between adriver's seat and an assistant driver's seat in a motor vehicle isformed in a complicated shape, and a metal mold having a complicatedshape is necessary for integrally molding it in a single piece, so thatthere is a risk that a molding defect of a finished product results.

Further, in a means for coupling a plurality of work pieces by screws orfasteners, not only is there a risk that the screw loosens due tovibrations, but also a manufacturing cost is increased. In addition,there is a risk of reduced strength or structural integrity.

With respect to the various problems mentioned above, the problem to besolved by the present invention is as follows.

A first object of the present invention is to provide a structure inwhich three or more work pieces made of thermoplastic material can bejoined by vibration welding into an integral sandwich shape.

A second object of the present invention is to provide a structure inwhich three or more work pieces made of a thermoplastic material can bejoined by vibration welding into a single assembly with superiorstrength.

A third object of the present invention is to provide a structure inwhich a finished product made of a thermoplastic material and having acomplicated shape can be manufactured with high quality without causingmanufacturing imperfections.

A fourth object of the present invention is to provide a structure inwhich the quality of a welded product can be improved by controllingrelative motion and a range of fit into the lower tool receiving blockso as to minimize variations in final height by a slide stabilizingmeans.

A fifth object of the present invention is to provide a structure inwhich quality of a welded product can be improved by controlling(adjusting) an elevation position of the lower tool block.

A sixth object of the present invention is to provide a structure inwhich a complicated and expensive metal mold is not required.

A seventh object of the present invention is to provide a structure inwhich a manufacturing labor can be reduced and waste can be effectivelyrecycled without sorting at the time of disposal, because the workpieces can be integrally joined without fixing means made of a differentmaterial such as a metal screws or the like.

An eighth object of the present invention is to provide a structure forwhich manufacturing time can significantly reduced, because vibrationwelding of the work pieces can be executed in accordance with sequentialmanufacturing steps.

Means for Solving the Problems

The means for achieving the objects mentioned above are as follows.

(1) A vibration welding apparatus for accomplishing the vibrationwelding of three or more work pieces, made of a thermoplastic material,to make them integral, in a sandwich shape, comprising:

an upper tool means supporting a first work piece so as to apply alateral vibratory motion to it by a vibration means; and

a lower tool means capable of supporting a plurality of second workpieces to be welded to at least both surfaces of the first work piece,

wherein the vibration welding apparatus is provided with a means capableof actuating the lower tool means in such a manner as to move the secondwork pieces in a height direction by an elevating means so as to alignwith the first work piece, and move the second work pieces toward thefirst work piece in a lateral direction by a slide actuating means so asto bring them into contact with the first work piece.

(2) A vibration welding apparatus as recited in the item (1) mentionedabove, wherein the vibration welding apparatus is provided with a slidestabilizing means capable of synchronizing a relative movement in alateral direction of right and left lower tool blocks.

(3) A vibration welding apparatus as recited in the item (1) mentionedabove, wherein the vibration welding apparatus is provided with a slidestabilizing means capable of stabilizing a relative movement in alateral direction of right and left lower tool blocks in a heightdirection.

(4) A vibration welding apparatus as recited in the item (1) mentionedabove, wherein the vibration welding apparatus is provided with adistance sensor capable of controlling an interval between right andleft lower tool blocks.

(5) A vibration welding apparatus as recited in the item (1) mentionedabove, wherein the vibration welding apparatus is provided with anelevation control lever regulating a height position of an elevationframe and a frame mechanical stop.

(6) A vibration welding method for executing vibration welding of threeor more work pieces made of a thermoplastic material to make themintegral in a sandwich shape, comprising the following sequential stepsof:

(A) a work piece installation step of installing a first work piece andat least a plurality of second work pieces to be welded to both sidesurfaces of the first work piece to an upper tool means and a pluralityof lower tool means arranged apart from each other respectively;

(B) a work piece contact step of making a plurality of lower tool meansascend and moving them close to each other so as to pressure-contact thefirst work piece and the second work pieces;

(C) a vibration welding step of generating a frictional heating betweenthe first work piece and the second work pieces pressure-contacted tothe first work piece by applying a lateral motion so as to partly meltthe work pieces, by the upper tool means; and

(D) a work piece cooling step of stopping the lateral motion so as toexecute natural cooling.

Effects of the Invention

Special effects of the present invention are as follows.

1. It is possible to execute vibration welding of at least three workpieces made of the thermoplastic material to make them integral in asandwich shape.

2. The strength of the finished product, obtained by the vibrationwelding, is superior.

3. It is possible to obtain a finished product, having a high quality,without requiring a metal mold having a complicated shape.

4. Since the finished product does not include different materials suchas a metal fastener, or the like, it is possible to dispose (recycle)without necessity of sorting for waste collection.

5. Since the manufacturing steps (sequence) can be reduced, productivityis improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a best mode in accordance with thepresent invention;

FIG. 2 is a functional block diagram of FIG. 1;

FIG. 3 is a view of a preceding step;

FIG. 4 is a view of a work setting step;

FIG. 5 is a view of a lower tool means ascending step;

FIG. 6 is a view of a work pressure-contact step;

FIG. 7 is a view of the vibration welding step;

FIG. 8 is a view of a drop prevention means retracing step;

FIG. 9 is a view of a center box releasing step;

FIG. 10 is a view of a right and left panels releasing step;

FIG. 11 is a view of a center console unloading step; and

FIG. 12 is a perspective view of parts of the center console.

PREFERRED EMBODIMENT OF THE INVENTION

A description will be given below of a best mode of the presentinvention with reference to FIGS. 1 to 11.

A vibration welding apparatus 1000 shown in FIG. 1 corresponds to aspecific example forming a center partition cum storage device (a centerconsole) arranged between a drive's seat and a assistant driver's seatin a motor vehicle, and has the following structure.

1. Summary of Vibration Welding Apparatus 1000

Various means mentioned below are arranged in a frame means 100constituted by a fixed frame 110 and an elevation frame 120.

In particular, in the elevation frame 120 ascended and descended by ahydraulic actuation means 200, there is mounted a lower tool means 500which is moved by a slide actuation means 300 and can hold a first workpiece (a center box) by an adsorption means 400, and in the fixed frame110, there is suspended an upper tool means 700 to which a lateralmotion is applied by a vibration generating means 600 and which can holda second work piece (right and left panels) by the adsorption means 400,wherein motions thereof are controlled by a control means 800 mentionedbelow.

2. Structure of each of Individual Means

(1) Upper Tool Means 700

For executing vibration welding of a center box CB and left and rightpanels LP and RP constituting a center console CC as shown in FIG. 12,the upper tool means 700 holding the center box CB is provided with twoupper tool receiving blocks 720 in a suspending manner under a lowersurface of an upper tool plate 710 connected to the fixed frame 110, asshown in FIG. 1 so as to form a pair, an outer side of a lower portionthereof is lined with a first cushioning material 721 to be brought intocontact with the center box CB, and the center box CB can be held by abox vacuum cup 410 of the adsorption means 400 being inserted into thecenter box CB.

Further, the structure is made such that a lateral motion is applied tothe upper tool plate 710 from a vibration generation means (a vibrator)600.

(2) Lower Tool Means 500

Left and right lower tool receiving blocks 510 and 520 arranged in aface to face manner in the lower tool means 500 are mounted on theelevation frame 120 so as to freely reciprocate in a lateral direction,are linearly moved close to each other and apart from each other by aslide actuation means 300 mentioned below, are provided with second andthird cushioning pieces 511 and 521 on facing surfaces to support theleft and right panels LP and RP constituting the center console CC, andcan hold the left and right panels LP and RP in a face to face manner byleft and right panel vacuum cups 420 and 430 of the adsorption means400.

The slide actuation means 300 mentioned above is structured such thatouter ends of piston rods 311 and 321 of first and second air cylinders310 and 320 arranged on the elevation frame 120 are respectively coupledto left and right flanges 513 and 523 provided on base frames 512 and522 of the left and right lower tool blocks 510 and 520 so as toprotrude uprightly.

Further, the respective base frames 512 and 522 are continuouslyprovided with a pair of racks 514 and 524 worked with a pinion 530, andare interposed with a slide stabilizing means 560 in which the sliders515 and 525 protruded under the lower surfaces of the base frames 512and 522 are engaged with rails 123 on the elevation frame 120.

A distance sensor 900 detecting an interval between the left and rightlower tool receiving blocks 510 and 520 which are moved close to eachother and apart from each other in accordance with the welding work, forexample, such a sensor detecting a change of the distance on the basisof a change of an eddy current flowing through a metal surface, isprovided between the left and right lower tool receiving blocks 510 and520.

A drop prevention means 920 of the center box CB is structured such thata holding plate 921 for preventing the center box CB held by the uppertool receiving block 710 from disengaging and dropping is fixed to anupper end of a piston lever 923 of a fluid cylinder 922, and can stablyhold the center box CB at a time of a welding process.

(3) Hydraulic Elevating Means 200

The elevation frame 120 is coupled to the piston lever 211 of thehydraulic cylinder 210, is structured such as to make the lower toolmeans 500 ascend and descend at a time of the welding process, and isstructured such that the elevation control lever 121 connected to theelevation frame 120 hits against the frame stopper 122 on the fixedframe 110, thereby regulating a height position of the elevation frame120 and improving a safety.

(4) Control Means 800

The control means 800 constituting a C.P.U is wired as shown in FIG. 2,and can precisely actuate and stop each of the means in correspondenceto a command from an operation instruction portion 810.

In particular, the hydraulic actuating means 200 is actuated by thecontrol means 800, thereby controlling the elevation frame 120 so as toascend and descend, holding the center box CB to the upper toolreceiving block 720 by the adsorption means 400 and holding the left andright panels LP and RP to the left and right lower tool receiving blocks510 and 520, respectively.

Further, the center box CB and the left and right panels LP and RP canbe pressure-contacted by moving the left and right lower tool receivingblocks 510 and 520 by the slide actuation means 300, and the vibrationwelding process can be executed by the vibration generation means 600.The interval between the left and right lower tool receiving blocks 510and 520 can be controlled by the distance sensor 900 for stabilizing thewelding process, and the height of the elevation frame 120 can be safelycontrolled by the frame stopper 122.

Further, the center box CB can be stably held by controlling the droppreventing means 920.

3. Work Piece

Three work pieces constituting the center console shown in FIG. 12 areall made of a thermoplastic material such as an ABS resin or a PPmaterial.

The center box CB positioned in the center and exposed to the vibrationwelding process is formed in a box shape.

Welding ribs LIB inwardly protruding toward the center box CB are formedin a laterally parallel shape on the left and right panels LP and RPpositioned in both sides of the center box CB and welded to the centerbox CB in a sandwich shape by the vibration welding.

4. Vibration Welding Method

A description will be given below of a welding method by the vibrationwelding apparatus 1000 mentioned above for each of the steps on thebasis of FIGS. 3 to 11.

(1) Preceding Step

As shown in FIG. 3, the elevation frame 120 is at a descent position,the left and right lower tool receiving blocks 510 and 520 are arrangedapart from each other, and the upper tool receiving block 720 isarranged apart from and above them, whereby a standby state is achieved.

(2) Work Setting Step

As shown in FIG. 4, the center box CB corresponding to the work piece isfitted to the upper tool receiving block 720, the left and right panelsLP and RP are inserted to the left and right tool receiving blocks 510and 520, and the adsorption means 400 is started, whereby the center boxCB and the left and right panels LP and RP are respectively adsorbed tothe upper tool receiving block 720 and the left and right lower toolreceiving blocks 510 and 520 by the box vacuum cup 410 and the left andright panel vacuum cups 420 and 430 respectively so as to be stablyheld.

(3) Lower Tool Means 500 Ascending Step

As shown in FIG. 5, the hydraulic cylinder 210 is started, the lowertool means 500 is made to ascend together with the elevation frame 120,and the left and right panels LP and RP are arrived at a positionproperly facing the center box CB.

With respect to the ascending amount of the elevation frame 120 at thistime, the elevation frame 120 can safely ascend until the elevationcontrol lever 121 is constrained to the stop position by the framestopper 122.

Further, the center box CB is supported from the lower surface and thedrop can be previously prevented by ascending of the holding plate 921coupled to the piston lever 923 of the hydraulic cylinder 922 of thedrop prevention means 920.

(4) Work Pressure-Contact Step

As shown in FIG. 6, the piston rods 311 and 321 of the first and secondair cylinders 310 and 320 are actuated as shown by arrows, the left andright tool receiving blocks 510 and 520 are moved in a direction comingclose to each other, and the center box CB is pinched in a sandwichshape by the left and right panels LP and RP, whereby the welding ribsLIB are set in a pressure-contact state.

At this time, since the slide stabilizing means 560 is interposedbetween each of the piston rods 311 and 321, the left and right toolreceiving blocks 510 and 520 are moved at a same distance, and arestably maintained by the rails 123 and the sliders 515 ad 525.

(5) Vibration Welding Step

As shown in FIG. 7, a lateral motion in a direction orthogonal to thepaper surface is applied to the upper tool receiving block 720 from avibrator 600 coupled to the upper tool plate 710, a frictional heatingis generated between the welding ribs LIB of the left and right panelsLP and RP and the center box CB, and leading ends of the welding ribsLIB are melted, whereby the left and right panels LP and RP and thecenter box CB are welded.

During the work, the first and second air cylinders 310 and 320 areadditionally actuated while detecting the distance of a melted portioncorresponding to a melt margin of the welding rib LIB by the distancesensor 900, and the welding process is promoted by bringing the left andright lower tool receiving blocks 510 and 520 closer slightly (about 3mm).

(6) Cooling Step

In a state of the step (5) mentioned above, the vibrator 600 is stoppedby a control means on the basis of the signal of the distance sensor900, and the position is held for a short moment (about 3 seconds) toremain ready for cooling and hardening.

(7) Drop Prevention Means 920 Retracting Step

As shown by an arrow in FIG. 8, the holding plate 921 is made to descendso as to be isolated from the lower surface of the center box CB.

(8) Center Box CB Releasing Step

As shown in FIG. 9, the operation of the box vacuum cup 410 of theadsorption means 400 is stopped, and the elevation frame 120 is made todescend, whereby the upper tool receiving block 720 is released from thecenter box.

(9) Left and Right Panels LP and RP Releasing Step

As shown in FIG. 10, the operation of the left and right panel vacuumcups 420 and 430 of the adsorption means 400 is stopped, and the firstand second air cylinders 310 and 320 are moved reverse in directions ofarrows, whereby the left and right panels LP and RP are released fromthe left and right lower tool receiving blocks 510 and 520.

(10) Center Console CC Unloading Step

As shown in FIG. 11, the center console CC formed by the steps mentionedabove is unloaded from the vibration welding apparatus 1000, and all thesteps are finished.

Embodiment

An embodiment of the vibration welding work is as follows.

1. Lateral motion frequency l... 100 Hz to 240 Hz

2. Pressure applied to work piece ... about 50 to 1000 kg

3. Melt margin ... about 3 mm

4. Welding time ... about 3 sec

5. Cooling time ... about 3 sec

The work piece is as follows.

1. Raw Material

ABS resin, acrylic resin, polycarbonate, polyethylene, polypropylene.

2. Dimension

Thickness of center box ... about 2 to 5 mm

Thickness of left and right panels ... about 2 to 5 mm

INDUSTRIAL APPLICABILITY

In accordance with the present invention, it is possible to shorten amanufacturing process so as to obtain a finished product having acomplicated shape and made of a thermoplastic material, it is possibleto make the finished product as compact as possible, and the rigiditythereof can be increased. Accordingly, the present invention has anextremely great industrial applicability in view of applicability tovarious plastic products.

1. A vibration welding method for executing vibration welding of atleast a first work piece and a plurality of second work pieces made of athermoplastic material to make said first work piece and said pluralityof second work pieces integral in a sandwich shape, comprising:installing said first work piece to an upper tool and installing saidplurality of second work pieces to a plurality of lower tools arrangedapart from each other, then moving said plurality of lower tools towardseach other in opposite directions such that said plurality of secondwork pieces pressure-contact said first work piece, and then generatinga frictional heating between said first work piece and said plurality ofsecond work pieces by laterally moving said upper tool, thus vibrationwelding said first work piece and said plurality of second work piecesby partial melting.
 2. The method of claim 1, further comprisingnaturally cooling said first work piece and said plurality of secondwork pieces by stopping lateral movement of said upper tool.